This should be a great flying plane, and perfect for your new covering technique! The extra drag of the biplane will require more power, but the extra wing area with also give you a slower flying model. I would love to see it fly at 14.5 inches, but it will be a winner at any scale.

Joe.

Hi Joe, do you reckon the setup as it stands - the AP05 with the 5030 prop giving 90g thrust, will haul this bipe around and give enough grunt to perform a few basic aerobatic manoeuvers?

Looking at the airframe now and being able to compare it to the others I think it will possibly be 80 - 85g, maybe a touch more. At that weight I think that a 'from level flight' loop would be quite a challenge. It may be that I need to produce a 1/22nd scale to bring the weight down for the power available.

Thanks CryHavoc, I hadn't seen that thread. Very interesting. There's hope for me yet although I suspect a lower AUW. I saw a couple of 'what's the weight?' questions in the thread - but didnt see any answers. My guess is somewhere between 45 - 55g.

I shall be including 4 channels in this one with the ailerons on the upper wings being controlled by a pushrod from the lower wing (that doesn't have ailerons) similar to that of the original aircraft.

Watching this with interest, was rooting for the B&V or the Lizzie but warming up to the Curtiss!

I think you'll be fine with regards to wing loading, the thing I'd watch out for is the wing incidence(s). On a plane with staggered wings you absolutly want the frontmost one (the top one in this case) to stall first so that the nose drops and the plane recovers. If the contrary is true you'll have a model that behaves capriciously at both low speeds and high G maneuvers.

I'd start with a simple chuck glider of the Curtiss, with zero incidence on the lower wing and stabilizer, and adjustable incidence on the top wing.
With this setup you'll in fact be closer to a high wing monoplane that has a second wing producing little to no lift along for the ride. The COG is set accordingly, about 1/3 from the leading edge of the top wing, that is to say quite a bit forwards of what you'd expect.

This of course is just a starting point, but it will allow you to gauge how much incidence you need on the upper wing to fly well, and how much effect the lower wing counteracts stabilizer input, and perhaps you'll find that the stab could benefit from a small increase in size.
The next step is to add incidence on the lower wing (less than the top wing!) and moving the COG rearwards. Followed by a lot of fiddling with wing incidences..
The nice things with a chuck glider like this is that it's quick to make, easy to adjust and you can ignore motor incidences, that bit comes later.

Watching this with interest, was rooting for the B&V or the Lizzie but warming up to the Curtiss!

I think you'll be fine with regards to wing loading, the thing I'd watch out for is the wing incidence(s). On a plane with staggered wings you absolutly want the frontmost one (the top one in this case) to stall first so that the nose drops and the plane recovers. If the contrary is true you'll have a model that behaves capriciously at both low speeds and high G maneuvers.

I'd start with a simple chuck glider of the Curtiss, with zero incidence on the lower wing and stabilizer, and adjustable incidence on the top wing.
With this setup you'll in fact be closer to a high wing monoplane that has a second wing producing little to no lift along for the ride. The COG is set accordingly, about 1/3 from the leading edge of the top wing, that is to say quite a bit forwards of what you'd expect.

This of course is just a starting point, but it will allow you to gauge how much incidence you need on the upper wing to fly well, and how much effect the lower wing counteracts stabilizer input, and perhaps you'll find that the stab could benefit from a small increase in size.
The next step is to add incidence on the lower wing (less than the top wing!) and moving the COG rearwards. Followed by a lot of fiddling with wing incidences..
The nice things with a chuck glider like this is that it's quick to make, easy to adjust and you can ignore motor incidences, that bit comes later.

This is super useful stuff Pouncer. The relative difference of incidence in my plans between wings is pretty much 0 at the moment. I will experiment with them now to try and get a better overall performance from her as I hadn't even thought of the beneficial effects of a difference in incidence between wings. I'm glad I started this thread now! Thank you.

Thanks Obake, They are all very sensible and would no doubt contribute to making a very flyable aircraft.

The great challenge with creating this aircraft is not only its performance but also designing so it can be built by others and probably the most important challenge is to make it so it doesn't break the bank.

The restrictions I have placed to keep spend down are, apart from the foam cutting tool, there will be no other tooling created to produce it. So in effect this means the aircraft has to be set up in a similar fashion to all the other aircraft in the sense that it uses the same Rx, wire control system, same plastics etc.

Interestingly I believe the Hawk only had ailerons on the upper wing, but they moved with a control rod from the lower wing. This plays right into my hands with the above considerations in mind and we should be able to replicate this scale detail quite accurately.

I had an epiphany yesterday on struts. I'd tried making the struts from wire and the concept was pretty sound as the wire would be clad with Depron & stickers to get it looking right. But on weighing them I wasnt impressed coming in at about 6g in total for all the ironwork!

Back to the drawing board and I was wracking my brain for ideas. I'd come to the conclusion that the struts should be laser cut or punched from some sort of rigid, lightweight material but for the life of me I couldn't think of anything suitable off the top of my head. Carbon fibre? some sort of new advanced and lightweight plastic? I was searching Google for inspiration for half an hour or so when a synapse connected in my brain - wood, you fool!

What better way of resolving the issue of building a vintage biplane by applying such a traditional material to the more advanced CF & foam.

I now have a sheet of 1.5mm thin plywood leaning against the wall ready to go under the knife (hope I get some time today). I've designed up the cabanes and interplanes so they can be easily fitted and the cabanes form a trapezoid 'box' to ensure accurate wing alignment.

I see these being laser'd in production. As soon as I have them cut (by hand) I'll post some pics for critical analysis!

It may be that I need to produce a 1/22nd scale to bring the weight down for the power available.

My friend Pete (mtflyr) and I have made several Depron/tissue micro WWI biplanes over the past year (threads are in this forum). We generally go for a 14.5"-15.5" wingspan (around 1/22) powered by a micro P-51 motor, using the AR6400 and on occasion, a single linear servo for ailerons. Weights are below 40g, with excellent control using RET. Batteries, of course, are 1S.

I would definitely use a one piece top wing (with a CF rod reinforcement - depending on wing thickness), and we generally use a two piece bottom wing with appropriate (scale) dihedral. Both wings are 1.5-2mm Depron.

Wing struts of thin plywood and gear struts of wire work well (and provide some gear shock absorbance). Paper shaped around the gear struts work well (light), but it looks like the large P-6 struts need to be made of Depron.

Given that your P-6 will have a heavier motor and battery, it will have to fly faster than the biplanes Pete and I have been doing, but then, that will be to scale. Would be good to have your P-6 not too much over 50g, I think. In that regard, you may want to consider not using the "neat" plastic brick holder as a weight saving measure.

I often take a stroll through yours & Pete's threads to marvel at the creations you both produce. They are incredible looking and flying.

I must admit this build is really pushing me to come up with solutions which I'm really enjoying and the advice that is being given is helping so much to shape those ideas and provide completely new ones that hadn't even crossed my mind.

I will piece the airframe together over the holidays in its 'skeletal' form so we can look at how all these ideas have been distilled. Didn't manage to get struts cut yesterday. Hopefully today I'll be able to get down to it.